JP4631414B2 - High tough, thick welded steel pipe with excellent sour resistance - Google Patents
High tough, thick welded steel pipe with excellent sour resistanceInfo
- Publication number
- JP4631414B2 JP4631414B2 JP2004349240A JP2004349240A JP4631414B2 JP 4631414 B2 JP4631414 B2 JP 4631414B2 JP 2004349240 A JP2004349240 A JP 2004349240A JP 2004349240 A JP2004349240 A JP 2004349240A JP 4631414 B2 JP4631414 B2 JP 4631414B2
- Authority
- JP
- Japan
- Prior art keywords
- less
- toughness
- weld metal
- steel pipe
- base material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Arc Welding In General (AREA)
Description
本発明は、耐サワー特性に優れた高靭性厚肉溶接鋼管に関し、詳しくは、鋼板からなる母材をＵＯＥ造管工程により管状に成形し、その母材が当接するシーム部を内外面１層盛りの大入熱ＳＡＷ（submerged arc welding：サブマージドアーク溶接）にて接合して製造された鋼管であって、その接合されたシーム部の溶接金属すなわちシーム溶接金属が高靭性を示すとともに、パイプラインとして接合する場所で円周溶接により継ぎ合わせるとき、鋼管の一方と他方とでシーム部がずれてＴ字形の継ぎ目が形成される部位であるＴ-クロス部が、前記円周溶接による熱サイクルを受けても硬度が上昇しにくい、耐サワー特性に優れた高靭性厚肉溶接鋼管に関する。 The present invention relates to a high toughness thick welded steel pipe excellent in sour resistance, and more specifically, a base material made of a steel plate is formed into a tubular shape by a UOE pipe forming process, and a seam portion with which the base material abuts is formed in one layer on the inner and outer surfaces. A steel pipe manufactured by joining a large amount of heat input SAW (submerged arc welding), where the welded seam weld metal, ie, the seam weld metal, exhibits high toughness, and the pipe T-cross part, which is a part where a seam part is displaced between one and the other of the steel pipes and a T-shaped seam is formed when seam welding is performed at a place to be joined as a line, a thermal cycle by the circumferential welding It relates to a high toughness thick welded steel pipe with excellent sour resistance, which does not easily increase in hardness even when subjected to stress.
近年の海底パイプラインに用いる鋼管は、石油・ガス開発の深海化、特に水深２０００ｍを超える海域への敷設を反映して厚肉、高靭性が要求される。さらに、輸送流体が高濃度のＨ２Ｓ（硫化水素）を含むサワー性のものである場合、耐ＨＩＣ（hydrogen induced cracking：水素誘起割れ）特性、さらに耐ＳＳＣ（sulfide stress corrosion cracking：硫化物応力腐食割れ）特性といった耐サワー特性が要求される。海底パイプラインに用いる鋼管の円周溶接には、通常、高能率ＧＭＡＷ（gas metal arc welding：ガスメタルアーク溶接）が用いられるが、能率向上のため予熱なしで施工される。よって、円周溶接によるＨＡＺ（heat affected zone：熱影響部）は急熱、急冷の熱履歴が与えられ、特にＴ-クロス部での硬度上昇が著しい。ＳＳＣはＨ２Ｓ環境下での腐食反応により鋼中に導入された水素が鋼の硬化部に集中する現象に起因した割れであり、耐ＳＣＣ特性の条件として敷設後の鋼管の全ての部位においてＨv（ヴィッカース硬度）２４８以下と規定するのが通例である。実質的には敷設後の鋼管の全ての部位において最も硬化する部位はＴ-クロス部であるので、この部位での最高硬度をＨv２４８以下とするのが課題となる。 Steel pipes used in recent submarine pipelines are required to have thick walls and high toughness reflecting the deepening of oil and gas development, especially the laying in waters exceeding 2000 m in depth. In addition, when the transport fluid is sour type containing a high concentration of H 2 S (hydrogen sulfide), it is resistant to HIC (hydrogen induced cracking), and further is resistant to SSC (sulfide stress corrosion cracking: sulfide stress). Corrosion cracking) characteristics such as sour resistance are required. High-efficiency GMAW (gas metal arc welding) is usually used for circumferential welding of steel pipes used in submarine pipelines, but it is applied without preheating to improve efficiency. Therefore, HAZ (heat affected zone) by circumferential welding is given a heat history of rapid heating and rapid cooling, and the hardness increase particularly at the T-cross portion is remarkable. SSC is a crack caused by the phenomenon that hydrogen introduced into steel due to corrosion reaction under H 2 S environment concentrates on the hardened part of steel, and in all parts of the steel pipe after laying as a condition of SCC resistance It is customary to specify Hv (Vickers hardness) of 248 or less. Since the most hardened portion of all the portions of the steel pipe after laying is the T-cross portion, it is a problem to make the maximum hardness at this portion Hv 248 or less.
ここでパイプライン上のＴ-クロス部13について図４を用いて説明しておく。図４は２つの溶接鋼管11を円周溶接して接合した部分の状況の見取図である。円周溶接による接合部はガスメタルアーク溶接ビード６を形成している。一方、各溶接鋼管11はシーム部12を有しているため、ガスメタルアーク溶接ビード６とシーム部12はアルファベットのＴに例えられる形状に会合する。この会合部分をＴ-クロス部13と呼ぶ。 Here, the T-cross portion 13 on the pipeline will be described with reference to FIG. FIG. 4 is a sketch of the situation where two welded steel pipes 11 are joined by circumferential welding. The joint by circumferential welding forms a gas metal arc welding bead 6. On the other hand, since each welded steel pipe 11 has a seam portion 12, the gas metal arc weld bead 6 and the seam portion 12 meet in a shape similar to the letter T. This meeting part is called a T-cross part 13.
一般にＴ-クロス部の硬度を低くするためには、円周溶接時にＴ-クロス部を含む溶接部の冷却速度を低くする、あるいはシーム溶接金属の焼入れ性を低減し高硬度のマルテンサイト（Martensite：以降Ｍと記すこともある。）組織の生成を抑止する方法が考えられる。溶接部の冷却速度を制御する方法としては、予熱・後熱処理、パス間温度制限などがあるが、高能率が要求される円周溶接工程においてこれらの工程、条件の追加は時間、コスト面において有益といえず実践的でない。 In general, in order to reduce the hardness of the T-cross part, the cooling rate of the welded part including the T-cross part is lowered during circumferential welding, or the hardenability of the seam weld metal is reduced to increase the hardness of the martensite. : Hereafter referred to as M.) A method of suppressing the generation of the organization is conceivable. Methods for controlling the cooling rate of the weld include preheating and post-heat treatment, temperature restriction between passes, etc., but in the circumferential welding process where high efficiency is required, adding these processes and conditions in terms of time and cost Not useful and impractical.
一方、シーム溶接金属の靭性を確保するために最も効果的な方法としては、Mo、Ti、Ｂを溶接材料より添加し、溶接金属の組織をアシキュラーフェライト（Acicular ferrite：以降、ＡＦと記すこともある。）と呼ばれる微細な組織にする方法が知られている。Tiは酸窒化物系介在物となり、ＡＦ変態の核生成サイトとして作用し、Ｂはフェライト変態前のオーステナイトの結晶粒界に偏析し、粒界の初析フェライトの粗大化を抑制する。大入熱となる内外面１層盛りによるシーム溶接においては、Ti、Ｂ添加のみでは粒界に粗大な初析フェライトが生成するのを完全には防止できないので、焼入れ性を高める元素であるMoを添加し、組織の均一微細化をはかる必要がある。（特許文献１，２，３）。 On the other hand, the most effective method for ensuring the toughness of the seam weld metal is to add Mo, Ti, B from the weld material and to describe the structure of the weld metal as acicular ferrite (hereinafter referred to as AF). There is also known a method for making a fine structure called "." Ti becomes an oxynitride inclusion and acts as a nucleation site for AF transformation. B segregates at the austenite grain boundary before ferrite transformation, and suppresses coarsening of proeutectoid ferrite at the grain boundary. In seam welding with a single layer of inner and outer surfaces with high heat input, the addition of Ti and B alone cannot completely prevent the formation of coarse pro-eutectoid ferrite at grain boundaries, so Mo is an element that enhances hardenability. It is necessary to make the structure uniform and fine. (Patent Documents 1, 2, and 3).
また、内外面１層盛りの大入熱ＳＡＷによる溶接鋼管の製造方法では、例えば内面から先に施工される溶接金属が、反対面例えば外面に施工される後行の溶接により再び加熱される（再熱される）。このとき再熱された溶接金属は部分的に脆化を引き起こすことが知られている。
特に２０００ｍを超える深海ラインパイプへの使用を目的とした、母材の厚さ２５ｍｍを超える厚肉鋼管では、シーム溶接の入熱を従来よりも増大させる必要があり、前述のように後行の溶接による先行の溶接金属の再熱領域は増大を免れない。すなわち、シーム溶接金属に対し、シャルピー衝撃試験結果の吸収エネルギー（以降、vＥと記すこともある。）、延性破面率（以降、ＳＡと記すこともある。）の両方で良好な特性を持たせるのはさらに困難である。 Especially for thick-walled steel pipes with a base metal thickness exceeding 25 mm, intended for use in deep-sea line pipes exceeding 2000 m, it is necessary to increase the heat input of seam welding compared to the conventional method. The reheat area of the previous weld metal by welding is subject to increase. That is, with respect to the seam weld metal, both the absorbed energy (hereinafter sometimes referred to as vE) of the Charpy impact test result and the ductile fracture surface ratio (hereinafter also referred to as SA) have good characteristics. It is even more difficult to do.
さらに、耐サワー特性を要求される鋼管はＳＳＣを回避するために、Ｔ-クロス部の硬度をＨv２４８以下とする必要がある。
本発明は、上述の問題に鑑み、内外面１層盛り溶接により製造される、母材の厚さ２５〜３５ｍｍの溶接鋼管において、シーム溶接金属の高靭性化と、鋼管同士を接合して形成されるＴ-クロス部における低硬度とを両立させた耐サワー特性に優れた高靭性厚肉溶接鋼管を提供することを目的とする。
Furthermore, in order to avoid SSC, a steel pipe that requires sour-resistant characteristics needs to have a hardness of Tv-cross portion of Hv248 or less.
In view of the above problems, the present invention is a welded steel pipe having a base metal thickness of 25 to 35 mm manufactured by one-layer inner and outer surface welding, and is formed by joining toughened seam weld metal and steel pipes. An object of the present invention is to provide a high-toughness thick welded steel pipe excellent in sour-resistant characteristics that achieves both low hardness in the T-cross portion.
発明者らは、上記目的を達成すべく鋭意検討を行い、以下のような知見を得た。
１）Mo、Ｂの低減は、シーム溶接金属の高靭性化およびＴ-クロス部における低硬度獲得に有効である。
２）加えて、次式で定義されるパラメータＰsscを用いると、Ｐsscの下限規定によりシーム溶接金属における高靭性獲得のための十分な焼入れ性を確保することができ、しかもＰsscの上限規定によりＴ-クロス部における低硬度を確保することができる。
Ｐssc＝Ｃ＋Si/15＋（Mn+Cu+Cr）/10＋Ni/30＋Mo/２＋Ｖ/５＋20×Ｂ−12×Ｎ−４×Ｏ
ただし、式中右辺の元素記号は溶接金属中でのその元素の含有量（質量％）を表す。なお、ＰsscのＰはparameterの頭文字であり、添字のsscは前記した耐ＳＳＣ特性を評価する意味から付けたものである。
The inventors have intensively studied to achieve the above object, and obtained the following knowledge.
1) Reduction of Mo and B is effective in increasing the toughness of the seam weld metal and obtaining low hardness in the T-cross part.
2) In addition, when the parameter Pssc defined by the following equation is used, sufficient hardenability for obtaining high toughness in the seam weld metal can be secured by the lower limit of Pssc, and T -Low hardness at the cross portion can be secured.
Pssc = C + Si / 15 + (Mn + Cu + Cr) / 10 + Ni / 30 + Mo / 2 + V / 5 + 20 × B-12 × N-4 × O
However, the element symbol on the right side of the formula represents the content (mass%) of the element in the weld metal. Note that P in Pssc is an acronym for parameter, and the subscript ssc is added for the purpose of evaluating the above-described SSC resistance.
本発明は、かかる知見に基づいてなされたものであって、その要旨は以下の通りである。
すなわち本発明は、厚さ２５〜３５ｍｍの鋼板からなる母材を管状に成形後そのシーム部を内外面１層盛り溶接してなる溶接鋼管であって、前記母材が、質量％で、Ｃ：0.01〜0.06％、Si：0.5％以下、Mn：0.8〜1.5％、Ｐ：0.010％以下、Ｓ：0.01％以下、Al：0.01〜0.10％、Cu：0.10〜0.70％、Ni：0.05〜1.00％、Nb：0.01〜0.08％、Ti：0.005〜0.05％、Ca：0.001〜0.005％、Ｏ：0.005％以下、Ｎ：0.005％以下、Cr：0.60％以下、Mo：0.10％以下、Ｖ：0.08％以下を含み、残部Feおよび不可避的不純物からなり、
シーム溶接金属が、質量％で、Ｃ：0.030〜0.060％、Si：0.5％以下、Mn：0.8〜1.8％、Cu：0.24〜0.50％、Cr：0.01〜0.50％、Ni：0.21〜0.50％、Nb：0.014〜0.07％、Ｖ：0.001〜0.07％、Mo：0.060〜0.12％、Ti：0.010〜0.03％、Ｂ：0.0005〜0.0015％、Ｎ：0.008％以下、Ｏ：0.035％以下を含み、かつ〔数１〕式で定義されるＰsscが0.140〜0.160％であり、残部Feおよび不可避的不純物からなることを特徴とする耐サワー特性に優れた高靭性厚肉溶接鋼管である。
〔数１〕
Ｐssc＝Ｃ＋Si/15＋（Mn+Cu+Cr）/10＋Ni/30＋Mo/２＋Ｖ/５＋20×Ｂ−12×Ｎ−４×Ｏ
ただし、式中右辺の元素記号は溶接金属中でのその元素の含有量（質量％）を表す。
This invention is made | formed based on this knowledge, Comprising: The summary is as follows.
That is, the present invention is a welded steel pipe formed by forming a base material made of a steel plate having a thickness of 25 to 35 mm into a tubular shape, and then welding the seam portion on one layer on the inner and outer surfaces. : 0.01 to 0.06%, Si: 0.5% or less, Mn: 0.8 to 1.5%, P: 0.010% or less, S: 0.01% or less, Al: 0.01 to 0.10%, Cu: 0.10 to 0.70%, Ni: 0.05 to 1.00 %, Nb: 0.01 to 0.08%, Ti: 0.005 to 0.05%, Ca: 0.001 to 0.005%, O: 0.005% or less, N: 0.005% or less , Cr: 0.60% or less, Mo: 0.10% or less, V: 0.08 % , Including the balance Fe and inevitable impurities,
Seam weld metal, in mass%, C: 0.030~0.060%, Si : 0.5% or less, Mn: 0.8~1.8%, Cu: 0.24~0.50%, Cr: 0.01~0.50%, Ni: 0.21~0.50%, Nb: 0.014-0.07% , V: 0.001-0.07% , Mo: 0.060-0.12% , Ti: 0.010-0.03%, B: 0.0005-0.0015%, N: 0.008% or less, O: 0.035% or less, and Pssc defined by the formula (1) is 0.140 to 0.160%, and consists of the balance Fe and unavoidable impurities, and is a high toughness thick welded steel pipe excellent in sour resistance.
[Equation 1]
Pssc = C + Si / 15 + (Mn + Cu + Cr) / 10 + Ni / 30 + Mo / 2 + V / 5 + 20 × B-12 × N-4 × O
However, the element symbol on the right side of the formula represents the content (mass%) of the element in the weld metal.
本発明によれば、母材の組成および内外面１層盛り溶接により形成されるシーム溶接金属の組成を最適化することができるので、シーム溶接金属の高靭性化とＴ-クロス部の低硬度とが両立した、優れた低温靭性を有する厚肉の低温用高靭性溶接鋼管が得られる。 According to the present invention, it is possible to optimize the composition of the base material and the composition of the seam weld metal formed by the inner and outer surface one-layer welding, so that the toughness of the seam weld metal is increased and the hardness of the T-cross portion is low. And a thick, high-temperature toughness welded steel pipe for low temperature with excellent low temperature toughness.
まず、母材の組成を前記本発明の範囲に限定した理由を述べる。なお、本発明では、組成の成分含有量の単位を質量％とし、％と略記する。
Ｃ：Ｃは、母材の強度と靭性に大きな影響を及ぼす元素であるが、0.01％未満では強度が不足し、一方、0.06％超では靭性に悪影響を及ぼすため、0.01〜0.06％とした。
Si：Siは、鋼の脱酸過程で必然的に含まれる元素であるが、0.5％超ではＨＡＺの靭性を劣化させるため、0.5％以下とした。なお、脱酸を十分に行うには、0.1％以上とすることが好ましい。
First, the reason why the composition of the base material is limited to the scope of the present invention will be described. In the present invention, the unit of the component content of the composition is mass% and abbreviated as%.
C: C is an element having a great influence on the strength and toughness of the base metal. However, if it is less than 0.01%, the strength is insufficient. On the other hand, if it exceeds 0.06%, the toughness is adversely affected.
Si: Si is an element that is inevitably included in the deoxidation process of steel, but if it exceeds 0.5%, the toughness of the HAZ is deteriorated, so the content was made 0.5% or less. In order to sufficiently perform deoxidation, the content is preferably 0.1% or more.
Mn：Mnは、母材の強度と靭性を同時に向上させる極めて重要な元素であるが、0.8％未満ではその効果に乏しく、一方、1.5％超では後述するＰ、Ｓの中心偏析等により靭性等に悪影響を及ぼすため、0.8〜1.5％とした。
Ｐ、Ｓ：Ｐ、Ｓは中心偏析を助長する元素であり、低いことが望ましく、Ｐは0.010％以下、Ｓは0.01％以下とした。
Mn: Mn is an extremely important element for improving the strength and toughness of the base material at the same time. However, if it is less than 0.8%, its effect is poor. On the other hand, if it exceeds 1.5%, the toughness is caused by P and S center segregation described later. In order to have an adverse effect on the content, it was set to 0.8 to 1.5%.
P, S: P and S are elements that promote central segregation, and are desirably low. P is 0.010% or less, and S is 0.01% or less.
Al：Alは、後記するTiと同様に鋼の脱酸過程で必然的に含まれる元素であるが、0.01％未満ではその効果に乏しく、一方、0.10％超ではAl系非金属介在物を増加させ、靭性を低下させるため、0.01〜0.10％とした。
Cu：Cuは、母材の強度を確保するために必要な元素であるが、0.10％未満ではその効果に乏しく、一方、0.70％を超えると母材およびＨＡＺの靭性を低下させるため、0.10〜0.70％とした。
Al: Al is an element that is inevitably contained in the deoxidation process of steel, as will be described later. However, if it is less than 0.01%, its effect is poor, whereas if it exceeds 0.10%, Al nonmetallic inclusions increase. In order to reduce toughness, the content was made 0.01 to 0.10%.
Cu: Cu is an element necessary for securing the strength of the base material. However, if it is less than 0.10%, its effect is poor. On the other hand, if it exceeds 0.70%, the toughness of the base material and the HAZ is reduced. 0.70%.
Ni：Niは、母材の強度と靭性を向上させる元素であるが、0.05％未満ではその効果に乏しく、一方、1.00％を超えるとＨＡＺが硬化するため、0.05〜1.00％とした。
Nb：Nbは、母材およびＨＡＺの強度と靭性を確保するために添加されるが、0.01％未満ではその効果に乏しく、一方、0.08％を超えると靭性に悪影響を及ぼすため、0.01〜0.08％とした。
Ni: Ni is an element that improves the strength and toughness of the base metal. However, if it is less than 0.05%, its effect is poor. On the other hand, if it exceeds 1.00%, the HAZ is hardened, so 0.05 to 1.00%.
Nb: Nb is added to ensure the strength and toughness of the base material and HAZ. However, if it is less than 0.01%, its effect is poor. On the other hand, if it exceeds 0.08%, the toughness is adversely affected, so 0.01 to 0.08% It was.
Ti：Tiは、母材の靭性確保に必要な元素であるが、0.005％未満ではその効果に乏しく、一方、0.05％を超えると母材の靭性を劣化させるため、0.005〜0.05％とした。
Ca：Caは、脱酸剤であるが、0.001％未満ではその効果に乏しく、一方、0.005％超では靭性を低下させるため、0.001〜0.005％とした。
Ｏ：Ｏは、不可避的に混入する元素であり、低いことが望ましいが、特に、0.005％を超えると靭性を低下させるため、0.005％以下とした。
Ti: Ti is an element necessary for ensuring the toughness of the base material. However, if it is less than 0.005%, its effect is poor. On the other hand, if it exceeds 0.05%, the toughness of the base material is deteriorated.
Ca: Ca is a deoxidizer, but if it is less than 0.001%, its effect is poor. On the other hand, if it exceeds 0.005%, the toughness is lowered, so 0.001 to 0.005% was set.
O: O is an element that is inevitably mixed, and is desirably low, but in particular, if it exceeds 0.005%, the toughness is reduced, so the content was made 0.005% or less.
Ｎ：Ｎは、Ｏと同様に不可避的に混入する元素であり、低いことが望ましいが、特に、0.005％を超えると靭性を低下させるため、0.005％以下とした。
本発明ではさらに、必要に応じて母材組成に次の元素を追加してもよい。
Cr：Crは、母材の強度を高めるために、必要に応じて添加しうるが、0.60％を超えるとＨＡＺの靭性を劣化させるため、0.60％以下が好ましい。より好ましくは0.10〜0.60％である。
N: N is an element that is inevitably mixed in the same manner as O, and is desirably low, but in particular, if it exceeds 0.005%, the toughness is reduced, so the content was made 0.005% or less.
In the present invention, the following elements may be added to the base material composition as necessary.
Cr: Cr may be added as necessary to increase the strength of the base material, but if it exceeds 0.60%, the HAZ toughness is deteriorated, so 0.60% or less is preferable. More preferably, it is 0.10 to 0.60%.
Mo：Moは、母材の強度を高めるために、必要に応じて添加しうるが、0.10％を超えるとＨＡＺが硬化するため、0.10％以下が好ましい。より好ましくは0.01〜0.10％である。
Ｖ：Ｖは、母材およびＨＡＺの強度と靭性を向上させるために、必要に応じて添加しうるが、0.08％を超えると靭性に悪影響を及ぼすため、0.08％以下が好ましい。より好ましくは0.01〜0.08％である。
Mo: Mo can be added as necessary to increase the strength of the base material. However, if it exceeds 0.10%, the HAZ is cured, so 0.10% or less is preferable. More preferably, it is 0.01 to 0.10%.
V: V may be added as necessary to improve the strength and toughness of the base material and the HAZ, but if over 0.08%, the toughness is adversely affected, so 0.08% or less is preferable. More preferably, it is 0.01 to 0.08%.
なお、本発明では、水素誘起割れ防止の観点から、母材中のCa、Ｓ、Ｏの含有量は、次の〔数２〕式で定義されるCa当量が1.0〜3.0％になる範囲内とすることが好ましい。Ca当量が1.0％未満では水素誘起割れ防止が不十分となり、一方、3.0％超では靭性を低下させる。
〔数２〕
Ca当量＝｛Ca−（0.18＋130×Ca）×Ｏ｝/（125×Ｓ）
ただし、式中右辺の元素記号は母材中のその元素の含有量（質量％）を表す。
In the present invention, from the viewpoint of preventing hydrogen-induced cracking, the content of Ca, S, and O in the base material is within a range where the Ca equivalent defined by the following [Equation 2] is 1.0 to 3.0%. It is preferable that If the Ca equivalent is less than 1.0%, the prevention of hydrogen-induced cracking is insufficient, while if it exceeds 3.0%, the toughness is lowered.
[Equation 2]
Ca equivalent = {Ca− (0.18 + 130 × Ca) × O} / (125 × S)
However, the element symbol on the right side in the formula represents the content (% by mass) of the element in the base material.
次に、シーム溶接金属の組成を前記本発明の範囲に限定した理由を述べる。溶接金属の組成は一部を除き、焼入れ熱処理による強度および靭性の上昇効果を目的に構成されている。以下では、上記効果を奏せしめる性質を「焼入れ性」と称する。
Ｃ：Ｃは焼入れ性を大きく高める成分であるが、0.030％未満では強度が不足し、一方、0.060％超では炭化物やマルテンサイトが生成しやすくなり、靭性が低下するとともにＴ-クロス部の硬度を上昇させるため、0.030〜0.060％とした。
Next, the reason why the composition of the seam weld metal is limited to the scope of the present invention will be described. The composition of the weld metal is configured for the purpose of increasing the strength and toughness by quenching heat treatment, except for a part. Hereinafter, the property that exerts the above effect is referred to as “hardenability”.
C: C is a component that greatly enhances the hardenability. However, if it is less than 0.030%, the strength is insufficient. On the other hand, if it exceeds 0.060%, carbides and martensite are likely to be formed, and the toughness is reduced and the hardness of the T-cross portion is reduced. Therefore, the content is set to 0.030 to 0.060%.
Si：Siは脱酸剤として添加されるが、焼入れ性を高める成分でもあるため過剰に添加されるとアッパーベイナイト（Upper Bainite：以降、ＵＢと記すこともある。）と呼ばれる粗大組織が生成し、靭性を低下させるほか、Ｔ-クロス部の硬度を上昇させるので、0.5％以下とした。好ましくは0.1〜0.5％である。
Mn：Mnは、脱酸剤および焼入れ性を高める成分として必要であるが、0.8％未満ではその効果に乏しく、一方、1.8％を超えるとＵＢが生成しやすくなり、靭性を低下させるとともに、Ｔ-クロス部の硬度を上昇させるので、0.8〜1.8％とした。
Si: Si is added as a deoxidizer, but it is also a component that enhances hardenability, so when added excessively, a coarse structure called Upper Bainite (hereinafter sometimes referred to as UB) is formed. In addition to lowering the toughness, the hardness of the T-cross part is increased, so the content was made 0.5% or less. Preferably it is 0.1 to 0.5%.
Mn: Mn is necessary as a deoxidizer and a component that enhances hardenability. However, if it is less than 0.8%, its effect is poor. On the other hand, if it exceeds 1.8%, UB tends to be generated and the toughness is reduced. -Since the hardness of the cloth part is increased, it is set to 0.8 to 1.8%.
Cu：Cuは、焼入れ性を高める成分であり、母材およびワイヤのメッキから混入する成分であるが、0.50％を超えると焼入れ性が過剰となり、靭性を低下させるとともに、Ｔ-クロス部の硬度を上昇させるので、0.50％以下とした。
Cr：Crは、焼入れ性を高める成分であり、母材からの混入により含有されるが、0.50％を超えると焼入れ性が過剰となり、靭性を低下させるとともに、Ｔ-クロス部の硬度を上昇させるので、0.50％以下とした。
Cu: Cu is a component that enhances hardenability, and is a component mixed from the base metal and wire plating. However, if it exceeds 0.50%, hardenability becomes excessive, lowering toughness and hardness of the T-cross part. Therefore, the content is made 0.50% or less.
Cr: Cr is a component that enhances hardenability, and is contained by mixing from the base material. However, if it exceeds 0.50%, hardenability becomes excessive, reducing toughness and increasing the hardness of the T-cross part. Therefore, it was 0.50% or less.
Ni：Niは、焼入れ性を高める成分であり、母材からの混入により含有されるが、0.50％を超えると焼入れ性が過剰となり、靭性を低下させるとともに、Ｔ-クロス部の硬度を上昇させるので、0.50％以下とした。
Nb：Nbは、焼入れ性を高める成分であり、母材からの混入により含有されるが、内面、外面とも0.07％を超えると焼入れ性が過剰となり、靭性を低下させるとともに、Ｔ-クロス部の硬度を上昇させるので、0.07％以下とした。
Ni: Ni is a component that enhances hardenability and is contained by mixing from the base material. However, if it exceeds 0.50%, hardenability becomes excessive, lowering toughness and increasing the hardness of the T-cross part. Therefore, it was 0.50% or less.
Nb: Nb is a component that enhances hardenability and is contained by mixing from the base material. However, if the content exceeds 0.07% on both the inner and outer surfaces, the hardenability becomes excessive, lowering the toughness and reducing the T-cross part. Since the hardness is increased, the content is set to 0.07% or less.
Ｖ：Ｖは、焼入れ性を高める成分であり、母材からの混入により含有されるが、内面、外面とも0.07％を超えると焼入れ性が過剰となり、靭性を低下させるとともに、Ｔ-クロス部の硬度を上昇させるので、0.07％以下とした。
Mo：Moは、焼入れ性を高める成分であり、溶接金属組織を微細化し靭性を向上させるが、0.12％超では、溶接金属再熱部を脆化させ、特に、Ｔ-クロス部の硬度を著しく上昇させるので、0.12％以下とした。
V: V is a component that enhances hardenability and is contained by mixing from the base material. However, if the content exceeds 0.07% on both the inner surface and the outer surface, the hardenability becomes excessive, and the toughness is reduced. Since the hardness is increased, the content is set to 0.07% or less.
Mo: Mo is a component that enhances hardenability and refines the weld metal structure to improve toughness. However, if it exceeds 0.12%, the weld metal reheat zone becomes brittle, and in particular, the hardness of the T-cross portion is remarkably increased. Since it raises, it was made into 0.12% or less.
Ti：Tiは、微細なフェライトを形成させて靭性を向上させるが、0.010％未満ではこの効果に乏しく、一方、0.03％超では固溶Tiの増加により焼入れ性が過剰に上昇してＴ-クロス部の硬化を招くので、0.010〜0.03％とした。
Ｂ：Ｂは、焼入れ性を大きく高める成分であり、Tiとの相乗効果によって微細なＡＦを形成させ靭性を向上させるが、0.0005％未満ではこの効果に乏しく、一方、0.0015％を超えるとＴ-クロス部の硬度を著しく上昇させるので、0.0005〜0.0015％とした。
Ti: Ti improves the toughness by forming fine ferrite, but if less than 0.010%, this effect is poor, while if over 0.03%, the hardenability increases excessively due to the increase in solid solution T-cross. Since this causes hardening of the part, it was set to 0.010 to 0.03%.
B: B is a component that greatly enhances the hardenability. By synergistic effect with Ti, fine AF is formed and the toughness is improved. However, if it is less than 0.0005%, this effect is poor. Since the hardness of the cloth portion is remarkably increased, the content is set to 0.0005 to 0.0015%.
Ｎ：Ｎは、溶接金属中に不可避的に含まれる成分であるが、0.008％を超えると介在物を増加させ、さらにＢと結合して粒界での初析フェライトの生成を促進し、靭性を低下させるので、0.008％以下とした。
Ｏ：Ｏは、溶接金属中に不可避的に含まれる成分であるが、0.035％を超えると介在物を増加させ、さらにＢと結合して粒界での初析フェライトの生成を促進し、靭性を低下させるので、0.035％以下とした。
N: N is a component inevitably contained in the weld metal, but when it exceeds 0.008%, inclusions are increased, and further bonded with B promotes the formation of pro-eutectoid ferrite at the grain boundary, and toughness. Therefore, the content was made 0.008% or less.
O: O is a component inevitably contained in the weld metal, but when it exceeds 0.035%, inclusions are increased, and further bonded with B promotes the formation of pro-eutectoid ferrite at the grain boundary, and toughness. Therefore, it was made 0.035% or less.
Ｐssc：Ｐsscは、溶接金属の焼入れ性を示す指標として発明者が導入したパラメータであり、Ｐsscが大きいことは、焼入れ性が高いことを示す。Ｐsscは前記した焼入れ性を高める元素の含有量を、焼入れ性に与える影響の大きい元素であるＣに等価な含有量に換算してＣ含有量に合算したものである。具体的には〔数１〕式で表現され、各元素に乗じる係数は、焼入れ性に与える影響の大きさを示す。なお、Ｂの焼入れ性を低めるＮ、Ｏには負の係数を乗じる。シーム溶接金属において、Ｐsscが0.140％未満では、焼入れ性が不足し、初析フェライトが生成して靭性が劣化する。一方、Ｐsscが0.160％超では、ＵＢ、Ｍ組織を生成しやすくなり、再熱部の脆化を助長してＴ-クロス部の硬度を上昇させる。よって、Ｐsscは、0.140〜0.160％の範囲に制限した。 Pssc: Pssc is a parameter introduced by the inventor as an index indicating the hardenability of the weld metal, and a large Pssc indicates that the hardenability is high. Pssc is obtained by converting the content of the element improving the hardenability into a content equivalent to C, which is an element having a large influence on the hardenability, and adding it to the C content. Specifically, the coefficient expressed by the formula [1] and multiplied by each element indicates the magnitude of influence on the hardenability. Note that N and O, which lower the hardenability of B, are multiplied by a negative coefficient. In a seam weld metal, if Pssc is less than 0.140%, hardenability is insufficient, proeutectoid ferrite is generated, and toughness deteriorates. On the other hand, when Pssc exceeds 0.160%, UB and M structures are easily generated, and embrittlement of the reheated part is promoted to increase the hardness of the T-cross part. Therefore, Pssc was limited to a range of 0.140 to 0.160%.
本発明の溶接鋼管を製造するには、本発明の母材組成に一致する厚さ２５〜３５ｍｍの鋼板を、例えばＵＯＥ造管工程等の冷間加工により管状に成形し、該成形した管のシーム部に、高塩基性溶融型フラックスおよび低炭素Mo-Ti-Ｂ系溶接ワイヤを用いて、内外面１層盛りのＳＡＷ施工をする方法が好ましく用いうる。高塩基性溶融型フラックスおよび低炭素Mo-Ti-Ｂ系溶接ワイヤを用いることで、溶接金属の組成を容易に本発明の溶接金属組成に一致させることができる。 In order to manufacture the welded steel pipe of the present invention, a steel plate having a thickness of 25 to 35 mm that matches the base material composition of the present invention is formed into a tubular shape by, for example, cold working such as a UOE pipe forming process. A method of performing SAW construction of a single layer on the inner and outer surfaces using a high basic melting type flux and a low carbon Mo—Ti—B welding wire in the seam portion can be preferably used. By using a high basic melting type flux and a low carbon Mo—Ti—B welding wire, the composition of the weld metal can be easily matched with the weld metal composition of the present invention.
表１に示す組成および厚さの鋼板ＰＡ、ＰＢ、ＰＣを母材として、ＵＯＥ造管工程により、４電極法でアークを発生させて内外面１層盛りのＳＡＷにてシーム溶接し、本発明の実施例、および本発明を逸脱する比較例に相当するＡＰＩ規格Ｘ６５クラスのＵＯＥ鋼管を製造した。このとき、溶接条件は表２に示す通り一定とし、開先形状も図１に示す通り一定とし、溶接材料に用いた高塩基性溶融型フラックスと低炭素Mo-Ti-Ｂ系溶接ワイヤとの組み合わせを種々変えることにより実施例および比較例を製造し分けた。実施例および比較例のシーム溶接金属の組成を表３に示す。また、実施例、比較例について後述の方法でＴ-クロス部を形成した。 Using steel plates PA, PB, and PC having the compositions and thicknesses shown in Table 1 as the base material, an arc is generated by the UOE pipe forming process, and seam welding is performed with SAW having a single layer on the inner and outer surfaces. The UOE steel pipe of API standard X65 class corresponding to the examples of the present invention and the comparative example deviating from the present invention was manufactured. At this time, the welding conditions are constant as shown in Table 2, the groove shape is also constant as shown in FIG. 1, and the high basic molten flux used for the welding material and the low carbon Mo—Ti—B welding wire are used. Examples and comparative examples were produced and divided by changing the combinations. Table 3 shows the compositions of the seam weld metals of Examples and Comparative Examples. Further, T-cross portions were formed by the methods described later for the examples and comparative examples.
実施例および比較例について、以下の要領でシーム溶接金属の靭性とＴ-クロス部の最高硬度を調査した。
（シーム溶接金属の靭性：）溶接終了後１０ｍｍ×１０ｍｍサイズのシャルピー衝撃試験片３を溶接継手の外面（図２(a)）、内面（図２(b)）、ルート（図２(c)）の３つの位置よりそれぞれ採取し、ＪＩＳ Ｚ２２４２に従いシャルピー衝撃試験を行う。試料採取位置は、外面は外表面から２ｍｍの位置、内面は内表面から２ｍｍの位置、ルートは外面と内面の溶接金属の溶融線が交わる２点（会合部）を通過する線が試験片中心線となる位置である。試験片の採取位置を図２に断面図で示す。
（Ｔ-クロス部の最高硬度：）円周溶接の模擬として、鋼管の外表面に、外面側シーム部長手方向と直交するように、ＣＯ2シールドガスを用いて入熱１０．０ｋJ/ｃｍでガスメタルアーク溶接ビードを形成し、Ｔ-クロス部を作製した。このガスメタルアーク溶接により再熱されたシーム溶接金属（外面溶接金属）２を硬さ試験箇所とするため、ガスメタルアーク溶接の溶接方向に垂直なＴ-クロス部の断面を露出させ、ガスメタルアーク溶接ビード６の溶融線７から圧痕８までの距離ａが圧痕８の対角線の長さｄ以内の位置で、ＪＩＳ Ｚ３１０１に従い荷重９８Ｎでヴィッカース硬度試験を行い、これをＴ-クロス部の最高硬度とする。試験箇所の概要を図３に示す。なお、ガスメタルアーク溶接に先立ち、シーム部の外面溶接金属を鋼管の外表面と平滑になるように研削した。
About the Example and the comparative example, the toughness of the seam weld metal and the maximum hardness of the T-cross part were investigated as follows.
(Toughness of seam weld metal :) After completion of welding, the Charpy impact test piece 3 of 10 mm × 10 mm size is applied to the outer surface (FIG. 2 (a)), inner surface (FIG. 2 (b)), route (FIG. 2 (c)). ) And the Charpy impact test according to JIS Z2242. The sampling position is 2 mm from the outer surface on the outer surface, 2 mm from the inner surface on the inner surface, and the route passes through the two points (meeting part) where the weld metal melt lines on the outer surface and inner surface intersect. This is the position to be a line. The sampling position of the test piece is shown in a sectional view in FIG.
(Maximum hardness of T-cross part :) As a simulation of circumferential welding, heat input is 10.0 kJ / cm using CO 2 shielding gas on the outer surface of the steel pipe so as to be orthogonal to the longitudinal direction of the outer seam part. A gas metal arc weld bead was formed to produce a T-cross part. In order to use the seam weld metal (outer surface weld metal) 2 reheated by gas metal arc welding as the hardness test location, the cross section of the T-cross portion perpendicular to the welding direction of gas metal arc welding is exposed, and the gas metal A Vickers hardness test was performed at a load 98N according to JIS Z3101 at a position where the distance a from the melt line 7 of the arc weld bead 6 to the indentation 8 was within the diagonal length d of the indentation 8, and this was the highest hardness of the T-cross part. And An outline of the test location is shown in FIG. Prior to gas metal arc welding, the outer surface weld metal of the seam portion was ground to be smooth with the outer surface of the steel pipe.
これらの調査結果を表４に示す。表３と表４を対比すると、比較例１、２、３では、Mo、Ｐsscが本発明範囲より過多であり、Ｔ-クロス部の最高高度がＨv２４８以下にならなかった。中でも比較例３では、Mo、Ｐsscが特に過多であるため、内面、ルート位置など再熱部を含む位置でのシャルピー衝撃値が低下した。また、比較例４については、Ｐsscが本発明範囲より過少なため、シャルピー衝撃値が著しく低下した。これに対し、実施例１、２、３、４においては、Ｔ-クロス部の最高硬度がＨv２４８以下を達成し、かつ、シャルピー衝撃値は吸収エネルギー１７１.５Ｊ以上かつ延性破面率８６.７％以上を達成した。 These survey results are shown in Table 4. Comparing Table 3 and Table 4, in Comparative Examples 1, 2, and 3, Mo and Pssc were excessive from the range of the present invention, and the maximum altitude of the T-cross portion did not become Hv248 or less. In particular, in Comparative Example 3, Mo and Pssc are particularly excessive, and thus the Charpy impact value at a position including the reheat portion such as the inner surface and the root position is lowered. Further, in Comparative Example 4, Pssc was excessively smaller than the range of the present invention, and thus the Charpy impact value was remarkably reduced. On the other hand, in Examples 1, 2, 3, and 4, the maximum hardness of the T-cross portion achieved Hv 248 or less, the Charpy impact value was an absorption energy of 171.5 J or more, and a ductile fracture surface ratio of 86.7. % Achieved.
本発明は、２０００ｍを超える深海ラインパイプに利用することができる。 The present invention can be used for a deep-sea line pipe exceeding 2000 m.
１ 内面溶接金属
２ 外面溶接金属
３ シャルピー衝撃試験片
４ ノッチ
５ 鋼管の外表面
６ ガスメタルアーク溶接ビード
７ 溶融線
８ 圧痕
10 母材
DESCRIPTION OF SYMBOLS 1 Inner surface weld metal 2 Outer surface weld metal 3 Charpy impact test piece 4 Notch 5 Outer surface of steel pipe 6 Gas metal arc welding bead 7 Melt line 8 Indentation
10 Base material
Claims (1)
シーム溶接金属が、質量％で、Ｃ：0.030〜0.060％、Si：0.5％以下、Mn：0.8〜1.8％、Cu：0.24〜0.50％、Cr：0.01〜0.50％、Ni：0.21〜0.50％、Nb：0.014〜0.07％、Ｖ：0.001〜0.07％、Mo：0.060〜0.12％、Ti：0.010〜0.03％、Ｂ：0.0005〜0.0015％、Ｎ：0.008％以下、Ｏ：0.035％以下を含み、かつ〔数１〕式で定義されるＰsscが0.140〜0.160％であり、残部Feおよび不可避的不純物からなることを特徴とする耐サワー特性に優れた高靭性厚肉溶接鋼管。
〔数１〕
Ｐssc＝Ｃ＋Si/15＋（Mn+Cu+Cr）/10＋Ni/30＋Mo/２＋Ｖ/５＋20×Ｂ−12×Ｎ−４×Ｏ
ただし、式中右辺の元素記号は溶接金属中でのその元素の含有量（質量％）を表す。 A welded steel pipe formed by forming a base material made of a steel plate having a thickness of 25 to 35 mm into a tubular shape and then welding the seam portion on one layer on the inner and outer surfaces, wherein the base material is in mass% and C: 0.01 to 0.06% , Si: 0.5% or less, Mn: 0.8 to 1.5%, P: 0.010% or less, S: 0.01% or less, Al: 0.01 to 0.10%, Cu: 0.10 to 0.70%, Ni: 0.05 to 1.00%, Nb: 0.01 -0.08%, Ti: 0.005-0.05%, Ca: 0.001-0.005%, O: 0.005% or less, N: 0.005% or less , Cr: 0.60% or less, Mo: 0.10% or less, V: 0.08% or less , It consists of the balance Fe and inevitable impurities,
Seam weld metal, in mass%, C: 0.030~0.060%, Si : 0.5% or less, Mn: 0.8~1.8%, Cu: 0.24~0.50%, Cr: 0.01~0.50%, Ni: 0.21~0.50%, Nb: 0.014-0.07% , V: 0.001-0.07% , Mo: 0.060-0.12% , Ti: 0.010-0.03%, B: 0.0005-0.0015%, N: 0.008% or less, O: 0.035% or less, and A high toughness thick welded steel pipe excellent in sour resistance, characterized in that Pssc defined by the formula (1) is 0.140 to 0.160%, and the balance is Fe and inevitable impurities.
[Equation 1]
Pssc = C + Si / 15 + (Mn + Cu + Cr) / 10 + Ni / 30 + Mo / 2 + V / 5 + 20 × B-12 × N-4 × O
However, the element symbol on the right side of the formula represents the content (mass%) of the element in the weld metal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004349240A JP4631414B2 (en) | 2003-12-02 | 2004-12-02 | High tough, thick welded steel pipe with excellent sour resistance |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003402886 | 2003-12-02 | ||
| JP2004349240A JP4631414B2 (en) | 2003-12-02 | 2004-12-02 | High tough, thick welded steel pipe with excellent sour resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2005186162A JP2005186162A (en) | 2005-07-14 |
| JP4631414B2 true JP4631414B2 (en) | 2011-02-16 |
Family
ID=34797497
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2004349240A Expired - Fee Related JP4631414B2 (en) | 2003-12-02 | 2004-12-02 | High tough, thick welded steel pipe with excellent sour resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4631414B2 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5870561B2 (en) * | 2011-09-06 | 2016-03-01 | Ｊｆｅスチール株式会社 | High-strength welded steel pipe with excellent tensile stress strength of 600 MPa or more with excellent resistance to sulfide stress corrosion cracking |
| JP5870664B2 (en) * | 2011-12-08 | 2016-03-01 | Ｊｆｅスチール株式会社 | High strength welded steel pipe and manufacturing method thereof |
| JP5870665B2 (en) * | 2011-12-08 | 2016-03-01 | Ｊｆｅスチール株式会社 | High-strength welded steel pipe with excellent tensile stress strength of 600 MPa or more with excellent resistance to sulfide stress corrosion cracking |
| JP6193206B2 (en) | 2013-12-11 | 2017-09-06 | 株式会社神戸製鋼所 | Steel plate and line pipe steel pipe with excellent sour resistance, HAZ toughness and HAZ hardness |
| JP2017078221A (en) | 2015-10-21 | 2017-04-27 | 株式会社神戸製鋼所 | Steel plate and joined body |
| CN109338213B (en) * | 2018-09-29 | 2021-01-26 | 南京钢铁股份有限公司 | X80M deep sea strain-resistant pipeline steel and rolling process |
| CN109234623B (en) * | 2018-09-29 | 2020-10-27 | 南京钢铁股份有限公司 | X80M deep-sea strain-resistant pipeline steel plate and rolling process |
| CN109811258B (en) * | 2019-01-21 | 2021-01-26 | 南京钢铁股份有限公司 | Deep-sea acid-resistant pipeline steel and rolling method |
| CN109811257A (en) * | 2019-01-21 | 2019-05-28 | 南京钢铁股份有限公司 | A kind of deep-sea acid-resistant pipeline steel and smelting process |
| CN109680204A (en) * | 2019-01-21 | 2019-04-26 | 南京钢铁股份有限公司 | A kind of deep-sea acid-resistant pipeline steel and production method |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06256894A (en) * | 1993-03-08 | 1994-09-13 | Nippon Steel Corp | High strength line pipe excellent in hydrogen induced cracking resistance |
| JPH07278659A (en) * | 1994-04-12 | 1995-10-24 | Nippon Steel Corp | Manufacture of steel plate for line pipe excellent in co2 corrosion resistance, sour resistance and low temperature toughness |
| JPH0892649A (en) * | 1994-07-27 | 1996-04-09 | Kawasaki Steel Corp | Production of high strength hot bend steel tube |
| JPH08199293A (en) * | 1995-01-24 | 1996-08-06 | Nippon Steel Corp | Sour resistant steel plate excellent in crack arrest characteristic |
| JPH091344A (en) * | 1995-06-14 | 1997-01-07 | Kawasaki Steel Corp | Low temp. high toughness uoe steel tube |
| JPH09296217A (en) * | 1996-05-02 | 1997-11-18 | Nippon Steel Corp | Production of high strength vent pipe excellent in low temperature toughness |
| JPH09295067A (en) * | 1996-05-02 | 1997-11-18 | Nippon Steel Corp | Manufacture of high strength bent pipe excellent in toughness at welded metal part |
| JP2001064749A (en) * | 1999-08-27 | 2001-03-13 | Kawasaki Steel Corp | Hic-resisting non-heat treated high tensile strength steel product excellent in toughness in weld heat-affected zone |
-
2004
- 2004-12-02 JP JP2004349240A patent/JP4631414B2/en not_active Expired - Fee Related
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06256894A (en) * | 1993-03-08 | 1994-09-13 | Nippon Steel Corp | High strength line pipe excellent in hydrogen induced cracking resistance |
| JPH07278659A (en) * | 1994-04-12 | 1995-10-24 | Nippon Steel Corp | Manufacture of steel plate for line pipe excellent in co2 corrosion resistance, sour resistance and low temperature toughness |
| JPH0892649A (en) * | 1994-07-27 | 1996-04-09 | Kawasaki Steel Corp | Production of high strength hot bend steel tube |
| JPH08199293A (en) * | 1995-01-24 | 1996-08-06 | Nippon Steel Corp | Sour resistant steel plate excellent in crack arrest characteristic |
| JPH091344A (en) * | 1995-06-14 | 1997-01-07 | Kawasaki Steel Corp | Low temp. high toughness uoe steel tube |
| JPH09296217A (en) * | 1996-05-02 | 1997-11-18 | Nippon Steel Corp | Production of high strength vent pipe excellent in low temperature toughness |
| JPH09295067A (en) * | 1996-05-02 | 1997-11-18 | Nippon Steel Corp | Manufacture of high strength bent pipe excellent in toughness at welded metal part |
| JP2001064749A (en) * | 1999-08-27 | 2001-03-13 | Kawasaki Steel Corp | Hic-resisting non-heat treated high tensile strength steel product excellent in toughness in weld heat-affected zone |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2005186162A (en) | 2005-07-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5061483B2 (en) | Manufacturing method of ultra high strength welded steel pipe | |
| JP4853575B2 (en) | High strength steel pipe for low temperature excellent in buckling resistance and weld heat affected zone toughness and method for producing the same | |
| JP4811166B2 (en) | Manufacturing method of super high strength welded steel pipe exceeding tensile strength 800MPa | |
| JP5217773B2 (en) | High-strength welded steel pipe for low temperature having a tensile strength of 570 MPa or more and 760 MPa or less excellent in weld heat-affected zone toughness and method for producing the same | |
| JP2003138340A (en) | Ultrahigh strength steel pipe with excellent toughness of weld zone, and its manufacturing method | |
| JP4655670B2 (en) | Manufacturing method of high strength welded steel pipe with low yield ratio and excellent weld toughness | |
| WO2013118585A1 (en) | Double pipe and welded structure utilizing same | |
| JP2009185368A (en) | Base material for clad steel plate having high strength and weld heat affected zone toughness, and method for producing the same | |
| JP4631414B2 (en) | High tough, thick welded steel pipe with excellent sour resistance | |
| JP2007260716A (en) | Method for producing ultrahigh strength welded steel pipe having excellent deformability | |
| JP2001001148A (en) | GAS SHIELD ARC WELDING OF THICK HIGH TENSILE STRENGTH STEEL PLATE OF AT LEAST 900 MPa CLASS | |
| JP3770106B2 (en) | High strength steel and its manufacturing method | |
| JP3045856B2 (en) | Method for producing high toughness Cu-containing high tensile steel | |
| MXPA97007729A (en) | Solded gasket that has excellent resistance to the fat | |
| JP4016800B2 (en) | Thick large-diameter straight UOE steel pipe that satisfies the strict toughness requirements of both the inner weld metal and the reheated part, and its manufacturing method | |
| JP3290247B2 (en) | Method for manufacturing high tensile strength and high toughness bent pipe with excellent corrosion resistance | |
| JP2002226947A (en) | Martensitic stainless steel welded joint having excellent strain aging resistance | |
| JP4396303B2 (en) | High strength welded steel pipe with excellent low temperature toughness | |
| JP2000256779A (en) | Ultrahigh strength steel tube excellent in toughness at low temperature, and its manufacture | |
| JP5040973B2 (en) | Method for producing martensitic stainless steel pipe circumferential welded joint | |
| JP4964480B2 (en) | High strength steel pipe excellent in toughness of welded portion and method for producing the same | |
| JP4765283B2 (en) | Method for producing martensitic stainless steel pipe circumferential welded joint | |
| JP4134974B2 (en) | High toughness UOE steel pipe for low temperature | |
| JP4424484B2 (en) | Welded joints with excellent cold cracking resistance and steel for welding materials | |
| JPH08253821A (en) | Production of welded joint having excellent fatigue strength |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20070927 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20100713 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20100727 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20100927 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20101019 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20101101 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4631414 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131126 Year of fee payment: 3 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |